Apparatus including reciprocating web feeding means for a continuously feeding web

ABSTRACT

A blister packaging machine is provided with a pair of alternating reciprocating clamps which feed a web of sheet material in a continuous motion through the machine by alternately engaging the web by the clamps during the advancing portions of their strokes and transferring engagement back and forth between the clamps while the clamps are moving forwardly at the same velocity. The clamps are driven by a cam and cam follower mechanism linked to the clamps. A movable flat bed work station is supported for movement with one of the clamps and has a working member which works upon the sheet by a reciprocating stroke against the sheet. The actuation of the clamps, the motion of the clamps, and the timing of the actuation of the working elements is derived from the cam mechanism. The machine is particularly useful in forming blister packages for pills and the like through the use of reciprocating dies.

United States Patent 1 Hamilton 1 May 22,1973

[54] APPARATUS INCLUDING Primary Examiner-Travis S. McGe heeRECIPROCATING WEB FEEDING Att0rney-Wood, l-lerron & Evans MEANS FOR ACONTINUOUSLY FEEDING WEB 7] AB TRA T [75] Inventor: Joel A. Hamilton,Englewood, NJ. A blister packaging machine is provided with a pair ofalternating reciprocating clamps which feed a web of [73] Asslgnee if? &Company sheet material in a continuous motion through the g machine byalternately engaging the web by the [22] Filed: May 27, 1971 clampsduring the advancing portions of their strokes and transferringengagement back and forth between [21] Appl 147507 the clamps while theclamps are moving forwardly at the same velocity. The clamps are drivenby a cam U-S. Cl. and cam follower mechanism to the clamps A 425/333movable flat bed work station is supported for move- CI- v B65b ment oneof the clamps and has a Fleld of Search member works upon the sheet areciprocat- 226/112; 83/277; 425/383 ing stroke against the sheet. Theactuation of the clamps, the motion of the clamps, and the timing of[56] References cued the actuation of the working elements is derivedfrom the cam The machine is particularly u scful in forming blisterpackages for pills and the like :iegerist through the use ofreciprocating dies troop 21 Claims, 9 Drawing Figures 1 a 59/ MAI/M47210/90 F91? #677 if j 4- a f 3 t w -3/- -33 vt -aa- ,r

f v ,5; i F 4/ 3/ A PATENIEWw 3,733,773

SHEET 1 [1F 4 INVENTO PATENTEU HAY 2 2 I973 SHEET 2 OF 4 PATENTED 2 2 3SHEET [1F 4 INVENTQR.

APPARATUS INCLUDING RECIPROCATING WEB FEEDING MEANS FOR A CONTINUOUSLYFEEDING'WEB The present invention relates-to apparatus for working uponcontinuously moving webs of sheet material with reciprocating flat bedworking elements and more particularly to the feeding of a continuouslymoving sheet material through packaging machines and the coordinating ofthe movements of the working elements therewith.

An increasingly common and widespread means of packaging small articleswhich are to be sold in small quantities is to package the articles inwhat is commonly referred to as blister packages. Such packages arefinding extensive use in the packaging of pills of capsule and tabletform. These packages are fabricated from thermoplastic sheet material inwhich individual compartments resembling bubbles or blisters have beenformed. The articles are individually packaged in each of thecompartments which are then hermetically sealed by the lamination ofanother plastic or foil material film over the sheet. Pills, forexample, packaged in this manner are thus protected from deteriorationdue to contact with air and moisture. When the pills are needed, theycan be individually withdrawn from their respective compartments by thebreaking of the seal through the laminated film.

The manufacture of the blister packages in its most economical forminvolves thermoforming the blister compartments in the thermoplasticsheet which is supplied in the form of a continuous web wound in a roll.The process used involves the feeding of the sheet material in the rollpast the series of work stations in which successive operations areperformed. These operations result in the forming of the blistercompartments, the loading of articles into the compartments, and thenthe sealing of the compartments, usually by the laminating of film alsosupplied from a roll. The loaded and sealed blister packages are thencut into packages of convenient quantities of articles.

The series of work stations is usually arranged so that first heat isapplied to the thermoplastic sheet to soften it, and then immediatelythereafter the sheet is brought into contact with forming dies whichshape it. These dies may include a mating die pair which is broughttogether against the sheet from opposite sides of the sheet, or mayinclude a single forming die in which pneumatic force is applied in theform of high pressure air or a vacuum to deform the sheet into thesingle die. After the blisters are thus formed, the articles are loadedby passing the web through a loading station which includes a fillingmachine such as a pill dropper.

The loaded compartments are then passed to a laminating station in whicha film material is laminated to seal the compartments. The film isusually a web supplied from a roll, and may be either thermoplasticmaterial, a metallic foil, or one of several other suitable materials.The lamination may involve the application of heat to cause the secondfilm to adhere to the sheet, but, frequently, the film is laminatedthrough the application of an adhesive. This process involves thepassing of the loaded sheet through an adhesiveapplying station and thena pressure laminating station. After the lamination is completed, theloaded and sealed blister packages are passed to a die station in whichmovable cutting dies are brought into contact with the sheet to severthe sheet into individual article containing packages.

In performing the operations which form the final package, the sheetmust be fed through the successive work stations. This may be done bycontinuously moving the sheet and designing the work stations in such amanner that they can effectively operate on the moving sheet.Alternately, the sheet may be intermittently advanced through the workstations which may be designed to effectively operate upon the sheetduring dwells in the feeding operation. I

From an operating point of view, a continuous feeding process is moredesirable in that it can be performed faster and in that it eliminatesproblems involved in accelerating and decelerating the sheet materialwhich usually is not structurally resistant to deformations or tearingwhich customarily result from such accelerations. The continuous feedingprocess, however, usually requires very expensive work stations. Forexample, the die forming station usually must include dies which engagethe sheet through a considerable portion of its movement along the path.A common type of die used for this is a rotating die which employsindividual die members mounted on the surface of a rotating cylinder.Such dies must be synchronized in their operation so that their speedconforms identically with that of the moving web. These dies arerelatively expensive, and because these are frequently interchanged toaccommodate various package sizes and configurations, provision for agreat number of such rotatable dies involves a considerable expense.

One'of the conventional means employed in driving the web in acontinuous manner through such a machine has been to use continuouslymoving feed rolls of the pinch roll type. Experience with these rolls,however, has found that a minor amount of slippage does occur whichmakes coordinating the motion of the dies and the web extremelydifficult and somewhat unsatisfactory.

When cheaper, planar or flat bed work members are used, it is necessarythat these members reciprocate in some manner in a path parallel to themoving web. In all prior art devices, it has been found considerablydifficult to effectively coordinate the velocity of the reciprocatingmembers such as dies with that of the continuous moving web.

In intermittent web motion type machines, the sheet handling has beensomewhat unsatisfactory in that the varying motion of the sheet into thework station coupled with the motion of the somewhat heavy and highinertia supply rolls puts great stress upon the sheet, and frequentlyresults in the tearing or deforming of the sheet. In order to alleviatethis problem to a degree, and to provide for continuous rotation of thesupply roll and intermittent feed of the web through the work stations,complicated festooning devices have been incorporated involving clutchand brake devices, etc. These devices have not entirely eliminated theweb handling problems and have added other design problems, particularlyrelating to the varying of the sizes of the packages and the length ofthe feeding strokes. Other disadvantages of intermittent web motion typemachines lies in the handling of the articles which tend to jump inhigher speed operations. Liquid materials pose a particularproblem inthis regard.

In addition to die forming work stations, similar difficulties have beenfound in connection with other oper- 3 ations such as the heatingoperation, the laminating operation, and the die cutting operation.

To overcome the disadvantages of the prior art, it is a principleobjective of the present invention to provide, particularly in apackaging machine, simple and reliable means for continuously feedingthe sheet mate rial and for precisely and positively synchronizing themotion of reciprocating flat bed work stations with the continuousmotion of thematerial.

It is a more specific objective of the present invention to provide asimple and effective reciprocating mechanism to impart a continuousfeeding motion to the web, and to drive reciprocating work stations atexactly the same speed as the moving web when they are working upon theweb.

It is another objective of the present invention to provide a low costflexible machine in which a positive mechanical drive mechanism andpositive mechanical linkages move both the web feeding elements and thework stations in unison.

The present invention is predicted in part upon the concept of impartinga continuous motion to a web by feeding the web through alternatingintermittent engagement of the web by oppositely moving reciprocatingfeed members. The present invention is further predicted upon theconcept of providing movable flat bed work stations mechanically linkedto one of the feed members and actuating it upon the forward portion ofthe feeding stroke so that the web will move at precisely the samevelocity as the feed member. The work station is actuated only when thefeed member is positively engaging the sheet to insure that there is noslippage between the sheet and the working elements.

In the preferred embodiment of the invention, a blister packagingmachine is provided with a pair of reciprocating clamps, each actuableto engage the sheet and to move it along its path. The clamps are driventhrough mechanical linkages which are in turn driven by a rotating cam.The clamps are timed so that, in alternating fashion, one will advancethe sheet while the other of the clamps is being returned to its initialposition. The clamps are further timed to provide that feedingengagement of the web is transferred from one clamp to the other clampat a time whenthe clamps are moving with the same forward velocity. Thework stations are coupled to either one of the clamps and are actuableonly when the respective clamp to which it is so coupled is engaged sothat the respective work station is always moving at precisely the samevelocity as the associated clamp, and thus the precise velocity as theweb upon which it is operating.

The advantages of the invention reside in the positive and reliablemeans for ascertaining continuous web motion, in the ability to usesimple and economical work station components, and in the ease inadapting the machine to products of differing sizes.

These and other-objectives and advantages of the present invention willbe more readily apparent from the following detailed description of thedrawings illuschine embodying principles of the present invention, inwhich:

FIG. 1 is a perspective view of a pill blister package which the presentinvention is useful in producing;

FIG. 2 is a block diagram of a blister packaging machine embodyingprinciples of the present invention;

trating one preferred form of blister packaging ma- FIG. 3 is anelevational view of the preferred embodiment of the machine of FIG. 2; 7

FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 3illustrating the mounting of the vertically reciprocatable heads in thework stations;

FIG. 5 is a cross-sectional view taken along line 55 of FIG. 3illustrating the'head actuating mechanism;

FIG. 6 is an elevational view of the head actuating mechanism of FIG. 5illustrating the mechanism in the head released condition;

FIG. 7 is a longitudinal cross-sectional view, partially broken away,illustrating the relative mountings of the clamps;

FIG. 8 is a diagram of the cam which imparts horizontal reciprocatingmotion to the clamps and machine head assemblies; and

FIG. 9 is a timing diagram illustrating the operation of the machine setforth in the figures above.

GENERAL DESCRIPTION A typical blister pack 10, as illustrated in FIG. 1,includes, for example, twelve compartments 11 which are formed in athermoplastic sheet 12. Each of the compartments 11, when forming afilled package 10, contains usually one pill 14. The compartments 11 arehermetically sealed by a film 16 which is laminated to the sheet 12 toclose the open ends of the compartments 1]. According to one preferredembodiment of the present invention, such packages are manufactured onan apparatus as illustrated in the block diagram of FIG. 2.

Referring to FIG. 2, a pill blister packaging machine 20 is illustratedin block diagram form having a supply roll 21 upon which is wound a webof the thermoplastic sheet material 12. The machine defines a webdirecting path 22 which the web of material 12 follows through themachine 20 from the supply roll 21 to the discharge end 24 of themachine 20. The machine 20 is provided with a plurality of work stations30 which include a heating station 31 positioned nearest the upstreamend of the machine 20 near the supply roll 21. The second work stationis a deforming station 32 positioned adjacent the heater station 31 tothe downstream end thereof. The heater station 31 includes work elementswhich apply heat to the sheet as it passes through the station to softenthe material 12 in order to condition it for deformation at the dieforming station 32. The die forming station 32 includes at least one diehaving a die element which defines the shapes of a compartment or set ofcompartments 11 which will be part of the package 10. These compartmentsmay include a pair of die members which move together from oppositesides of the material 12 to form the blisters or bubble compartments 11in the sheet material 12. In accordance with the present invention,these die elements are reciprocating die elements which move together ina path perpendicular to that of the sheet material 12.

The sheet 12 which emerges from the work station 32 is passed to a workstation 33 which is a pill dropper which operates to insert pills intothe individual com- I. partments 11 formed in the sheet 12. The sheetcontaining the filled compartments is then advanced to a laminatingstation 34 which applies the film 16 to seal the pill compartments. Thefilm 16 is supplied in web form from a roll 17 and is directed around aroll 18 into a path overlying the sheet 12. The station 34 operateseither by a roll contact or preferably by a stamping motion to securethe film 16 to the sheet 12. The sealed compartments are then advancedto a cutting station 35 which contains preferably a set of die cuttingelements which move together in a reciprocating path to both cut thepackages into individual discrete sets of pill compartments and to scorethe packages for folding, if desired. The packages emerging from thestation 35 are completely formed packages 10 and are discharged from thedischarge end of the machine 24.

While all of the work stations 30 may be of conven tional design, thepresent invention is provided with the aim of allowing for the use ofreciprocating type work elements with the maximum of convenience andreli ability. Accordingly, when such elements are incorporated in any ofthe work stations 30, the present invention provides a means of insuringthat, while the work station is actuated, it is moving at precisely thesame speed as the sheet 12 upon which it is operating.

Accordingly, the present invention provides sheet advancing units whichemploy two pairs of elongated clamping elements 41 and 42 adapted togrip the edge of the sheet 12 along an extended portion of its lengthand to move it in a forward direction through the machine 10. Each ofthe pairs of clamps 41 and 42 are individually but synchronously drivenin reciprocating movement along the path 22 by a cam drive unit 43. Thecam drive unit 43 serves to separately drive the clamps 41 and 42through linkages 44 and 45, respectively. The pairs of clamps 41 and 42are driven at an approximately constant velocity through an advancingstroke of relatively long duration. Each clamp is retracted during areturn stroke of shorter duration, with one clamp pair being retractedwhile the other is being advanced. In this manner, the advancing strokesof the clamp pairs will overlap so that they will both be moving forwardat the same velocity, preferably at approximately the same velocity asthe constant forward velocity attained during most of the forwardportion of the advancing stroke. During the advancing stroke, the clampis engaged, while during the returning stroke the clamp is disengaged.Both clamps, however, are simultaneously engaged'momentarily at thebeginning and end portions of the strokes during which they are bothmoving forward at the same constant velocity. During this momentaryperiod, engagement is transferred from one clamp to the other to feedthe web in a smooth and uniform manner through the machine 10. It willbe seen from discussion herein and which follows that it will not beabsolutely essential that the advancing of the sheet be perfectlyuniform. This is primarily due to the fact that the work stations, whenoperating, will always be moving at precisely the same speed as theadvancing web due to its positive and direct link to the advancingclamp.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT Referring to FIGS. 3 and 4,the pill packing machine which was illustrated diagrammatically in FIG.2 is shown in detail. Four of the five work stations 30 are shown ascarried upon two machine head assemblies 71 and 72. Each of theseassemblies includes a lower head 73 and an upper head 74, each slideablymounted to move vertically upon the machine head assemblies. Each of theassemblies 71 and 72 includes a vertical support plate 76 pivotallymounted at its lower end to the machine frame 77 through a pivotal axis78. The

upper end of the plate 76 is rigidly attached to a cross plate 79. AT-shaped link 81 is pivotally mounted at its cross point by a pin 82 tothe plate 76. To the lower portion of the T-shaped link 81 is slideablymounted the lower machine head 73 through a bracket 83. The uppermachine head 74 is slideably mounted to the upper extension of the link81 by slideable bearing blocks 85 which are mounted in a groove 86 ofthe upper member of the link 81. The remote end of the horizontalportion of the link 81 is pivotally attached at point 88 to a verticalbar 89 which is in turn pivotally mounted to the frame 77 at point 90.The frame 77, the plate 76, the link 81, and the bar 89 form aparallelogram which will maintain the orientation of the heads 72 and 73in a vertical attitude.

This parallelogram configuration of the machine head assemblies 71 and72 are rocked in a reciprocating manner through linkages 92 attached torocker arms 93 which carry cam followers 94 and 95 which are driven by acam 96 (FIG. 8). The reciprocating stroke is actually an are but it isrelatively short compared to the length of the plate 76 and the bar 89.Thus, the vertical motion is insignificant and the motion issubstantially horizontal. The stroke length is varied by remounting thelink 92 between different holes 84 and 87 in the members 76 and 93,respectively.

The raising and lowering of the upper and lower machine heads 74 and 73are achieved through linkages 91 which are driven by rocker arms 97carrying the cam followers 98 and 99 respectively, which are driven bythe cam 100. The details of the mechanism for raising and lowering theseheads 73 and 74 will be understood more clearly in connection with FIGS.4 and 5 below. While a mechanical actuator is shown, it is contemplatedthat other means such as electrical, hydraulic, or pneumatic actuatorscould be used satisfactorily since this motion need not be criticallymaintained.

The mounting of the work stations 31-35 are as follows: the heaterstation and the die forming station are both mounted to the heads of themachine head assembly 71 and move in unison under the control of the camfollower 99. The loader 33 may be any conventional pill dropper and ispositioned downstream from the machine head assembly 71. The laminatingstation and the trimming station 34 and 35, respectively, are mounted tothe machine head assembly 72 and move in unison under the control of thecam follower 98. The clamps 41 and 42 extend longitudinally of themachine 20 along the path 22 of the sheet 12. The outer clamp 42 ispivotally supported at the machine head assembly 71, while the innerclamp 41 is pivotally supported at the machine head assembly 72. Theclamps 41 and 42 are slideably mounted with respect to each other andtherefore support each other in a horizontal orientation, but each movesindividually in unison with the machine heads 71 or 72 to which they arepivotally mounted.

The machine head actuating mechanism is best shown in FIGS. 4-6 withreference also to FIG. 3. FIG. 4 illustrates the machine head assembly72 with the heads 73 and 74 in the actuated or closed position. Asshown, the head assembly 72 includes the rigidly coattached vertical andtop plates 76 and 79. To the side plate 76 is slideably mounted theupper head 74 through the slide bearing assembly 85 which rides in theslot 86 in the T-shaped link 81 which is pivotally attached at point 82to the plate 76. The lower head is similarly slideably mounted withrespect to the plate 76. This slideable mounting is achieved through therigid mounting to the bracket 83 which slideably engages the T-shapedmember 81. The lower head 73 is driven up and down through the lowerhead drive link 105 which is pivotally mounted to the lower head supportbracket 83 through the pivot shaft 106. Similarly, the upper head 74 isdriven by the upper head drive link 107 which is pivotally mounted tothe upper head 74 by the shaft 108.

The links 105 and 107 are driven by the head actuating mechanism shownin FIGS. and 6. Referring to these figures, a torsion bar 121 issupported on the pivot shaft 78. A lever 122 is rigidly secured to thecenter of the torsion bar and linked through the linkage 91 to therocker arm 97 to be driven by the cam follower 98. Secured to the endsof the torsion bar 121 are levers 124 which are pivotally attached tothe lower end of the lower head drive rods 105. The lower ends of theupper head actuator rods 107 are pivotally attached by a pin 126 to theend of the torsion bar 121. When the head is in its actuated position,the pin 126 is directly below the shaft 78. In FIG. 3, the head assembly72 is illustrated in the head actuated condition, while the head 71 isillustrated in the head de-actuated or released condition.

Referring again to FIG. 4, the clamp structure is illustrated in whichthe clamps are arranged in a superimposed relationship with an innerclamp 51 spaced along the edge of the sheet 12 and surrounded by theouter clamp 52. Each of the clamps form one corresponding clamp of eachof the pairs of clamps which are arranged in corresponding positions onopposite sides of the web 12 to simultaneously grip the edges thereof.The inner clamps 51 make up the clamp pair 41, while the outer clamps 52make up the clamp pair 42.

Each inner clamp 51 includes a relatively fixed element 53 and a movableclamp element 54 which is spring mounted through the integrally formedspring 55 secured to the wall 56 of the clamp to which the relativelystationary element 53 is an integral part. The spring element 55normally biases the movable clamp element 54 away from the fixed element53 to thereby release the sheet 12. The clamp 51 is actuated to grip thesheet 12 by the inflation of an elastic hose 57 positioned within thecurve of the spring 55 to urge the movable element 54 toward the fixedelement 53. The inner clamp 51 is slideably mounted to the outer clamp53 by bolts 58 extending through a slot 59 and secured to the innerclamp drive bar 60.

Each outer clamp 52 includes a relatively fixed element 63 and a movableclamp element 64 which is spring mounted through the integrally formedspring 65 secured to the wall 66 of the clamp 52 to which the relativelystationary element 63 is an integral part. The spring element 65normally biases the movable clamp element 64 away from the fixed element63 to'thereby release the sheet 12. The clamp 53 is actuated to grip thesheet 12 by the inflation of an elastic hose 67 positioned within thecurve of the spring 65 to urge the movable element 64 toward the fixedelement 63.

The clamp assemblies are supported from a bracket 131 suspended from theupper plate 79 and each of the machine head assemblies 71 and 72. Asillustrated in FIG. 4, the bracket 131 is driveably connected through apivot pin 132 to the slide bar 60 to -drive the inner clamp 41. However,at the station 71, the bracket 131 would be driveably connected to theclamp 42 with the pivot shaft 132 extending through a slot in the slidebar 58 and engaging the wall structure of the clamp 42. The slideablemounting of the clamps 41 and 42 with respect to each other isillustrated more clearly in connection with FIG. 7. As illustrated, theslide bar 60 and the back plate 133 of the outer clamp are slideablysupported by each other through combinations of slide bearings 137secured to one of the members 60 or 133 and adapted to slide in a slot59 of the other of these members. Accommodation of different web widthsis achieved by the mounting of the bracket on the top plate 99 bysetting the screw 124 at different points along the slot 128.

The operation of the machine can best be understood by reference toFIGS. 8 and 9, which illustrate the relation of the cams 96 and 100 inconnection with the machine functions. Referring to cam 96, six regionsare illustrated. Three of these regions 141, 142, and 143, illustrate aregion of continuously increasing radius through which the cam followers94 and 95, and consequently their respective driven heads and clampmembers, will be moving in a forward direction at a uniform velocity. Ascan be seen, the combined region spans an arc of more than 180. Theregions 141 and 143 thus represent the regions which the cam followers94 and will both be moving the same direction with the same velocity.When the cam followers 94 and 95 are within this region, the actuationand de-actuation of the clamps will occur as will be seen in connectionwith the timing diagram of FIG. 9. During the time in which the camfollowers 94 and 95 are within the cam regions 145 and 146, the cams andtheir associated driven elements will be accelerating and decelerating,respectively to or from their forward movement. The region 147represents the region in which the elements will be moving in thereverse direction and returning to their initial positions.

The cam is a groove type cam which has essentially two operating radii,the first or larger radius spans the major portion of the cam andrepresents the condition in which the heads will be de-actuated or intheir opened condition. The lower portion therefore represents theregion in which the heads will be in their closed or actuated condition.These regions aredesignated 151 and 152, respectively, in FIG. 3.

The timing diagram of FIG. 9 illustrates the various machine functionsincluding the head and clamp horizontal motion as controlled by the cam96, the head vertical reciprocating motion as controlled by the cam 100,and the actuation of the clamp assemblies 41 and 42 controlled by othercams not shown on the shaft of the cams 96 and 100. The timingrelationships are illustrated with respect to the top dead centerposition of the cam assembly. Curve A represents the relative horizontalposition of the machine head assembly 72 and the inner clamp 41 asdriven by the cam follower 94. Curve 8 illustrates the relativehorizontal position of the heads 71 and the outer clamp 42 as driven bythe cam follower 95. Curve C represents the actuated condition of theclamp 41, while curve D represents the actuated condition of the clamp42. Curves E and F represent the closed or actuated conditions of thehead assemblies 72 and 71, respectively, as controlled by the camfollowers 98 and 99 respectively. The machine, in all the figures, isillustrated in the condition in which the cam is in top dead center asillustrated by the left hand vertical coordinate of the timing diagramof FIG.

What is claimed is:

1. A machine for forming, filling, and sealing packages from a web ofmaterial being continuously transported past a series of work stations,said machine comprising:

means for continuously advancing said web along a path past said workstations including:

a. a pair of clamp assemblies each adapted to engage said web,

b. means for mounting said clamp assemblies for reciprocating movementin forward and reverse strokes'along said path, I

c. a rotatable cam,

d. a pair of cam followers,

e. means for linking each of said cam followers to a different one ofsaid clamp asse'mblies,'ari'd f. said cam and cam followers beingadapted to reciprocate said clamp assemblies in an out-ofphaserelationship with each other;

at least one of said work stations mounted for reciprocating movementwith one of said clamp assemblies; V v

said movable work station including flat bed working elements movablewith respect to said work station in a path approximately perpendicularto that of ,said web and the movement of said work station;

means for actuating said working elements to work upon said web whilethe clamp assembly with which the work station is mounted is engagingand advancing said web; and

clamp actuating means for alternately closing said clampassembliesduring a portion of their forward strokes, said clampassemblies being simultaneously closed only when moving at the samevelocity during the forward stroke; I

whereby said web is continuously moved in a forward direction by thealternative action of said clamp assemblies.

2. A machine according to claim 1 I wherein said working elementsinclude:

a reciprocating die assembly operable to deform said web when actuated.

3. A packaging machine having forming, filling, and sealing means forworking upon a continuous web of sheet material, said machinecomprising? means for directing said web in a predetermined path;

a flat bed work station positioned along said path;

means for continuously advancing said web in a forward direction alongsaid path past said work station, said advancing means including firstand second feed elements, each of said feed elements being mounted forreciprocating movement along said path and each being adapted tointermittently engage and advance said web durin g the forward motion ofthe element; and

drive means for alternately reciprocating said feed elements, said drivemeans including a mechanical linkage connected between said feedelements.

4. A machine according to claim 3 wherein:

said work station is fixedly linked to one of said feed elements forreciprocating movement therewith.

5. A machine according to claim 4 wherein said work station includes:

a working member for working upon said web and mounted for reciprocatingmovement on said movable work station in a path approximatelyperpendicular to the path of said web and said work station.

6. A machine according to claim 5 further comprising:

means for actuating said working element to work upon said web while thesheet feed member with which thework station is mounted is engaging andadvancing said web.

7. A machine according to claim 3 further comprising:

means'for actuating said feed elements to engage said web during theforward movement of the element but to disengage said web during thereturn movement of the feed element;

said feed elements being moved at the same velocity in the forwarddirection during periods near the beginnings and the ends of theirforward movements, said elements momentarily simultaneously engagingsaid web during said periods;

whereby said web is continuously being engaged and advanced by at leastone of said elements.

8. A machine according to claim 7 wherein:

said elements are driven at an approximately constant velocity whenengaging said web.

9. A blister packaging machine comprising:

a supply of thermoplastic sheet material in the form of a web; I i i aplurality of work stations for successively performing, upon saidweb,'the operations 'of l. heating a portion of said web,

2. deforming a heated portion of said web to form a plurality ofblister-like compartments therein,

3. loading articles into said formed compartments,

4. laminating a film to a portion of said web to seal said loadedcompartments, and

5. trimming a sealed portion of said web to form a package;and

meansfor continuously advancing said web along a 'path past said workstation comprising:

a. a pair of clamp assemblies adapted to engage 'said web,

b. means for mounting said clamp assemblies for reciprocating movementin forward and reverse strokes along said path,

c. a rotatable cam,

d. a pair of cam followers,

e. means for linking each of said cam followers to a different one ofsaid clamp assemblies,

f. said cam and cam followers being adapted to reciprocate said clampassemblies in out-of phase relationship with each other; and

g. clamp actuating means for alternately closing .said clamp assembliesduring a portion of their forward strokes, said clamp assemblies beingsimultaneously actuated only when moving at the same velocity during theforward stroke; whereby said web is continuously moved in a forwarddirection by the alternative action of said clamp assemblies.

10. A machine according to claim 9 wherein:

at least one of said work stations mounted for reciprocating movementwith said clamp assemblies;

said movable work station including working elements movable withrespect to said work station in II. A machine according to claim whereinsaid movable work station includes:

a die forming assembly having an element movable against said web todeform said web while said station is moving at the same velocity assaid web.

12. A machine according to claim 10 wherein said movable work stationincludes:

a heater assembly having an element movable against said web to heatsaid web while said station is moving at the same velocity as said web.

13. A machine according to claim 10 wherein said movable work stationincludes:

a press assembly having an element movable against said web to laminateto said web an interposing film material while said station is moving atthe same velocity as said web.

14. A machine according to claim 10 wherein said movable work stationincludes:

a die cutting assembly having an element movable against said web to cutsaid web while said station is moving at the same. velocity as said web.

15. in a machine for working upon a web ofsheet material at aworkstation, means for continuously advancing said web along a path pastsaid work station com-. prising:

a pair of clamp assemblies adapted to engage said web;

means for mounting said clamp assemblies for reciprocatingmovement inforward and reverse strokes along said path,

a rotatable cam;

a pair of cam followers;

means for linking each of said cam followers to a different one of saidclamp assemblies;

said cam and cam followers being adapted to reciprocate said clampassemblies in out-of-phase relationship with each other; and

clamp actuating means for alternately closing said clamp assembliesduring a portion of their forward strokes, said clamp assemblies beingsimultaneously actuated only when moving at the same velocity during theforward stroke;

whereby said web is continuously moved in a forward direction by thealternative action of said clamp as-. semblies. v

16. Advancing means according to claim 15 wherein:

each of said clamp assemblies includes a pair of elongated clampsextending along said path and on opposite edges of said web, said clampassemblies being positioned to engage said edges when closed.

17. Advancing means according to claim 15 wherein:

said cam includes a major portion of uniformly increasing radius; and

said cam followers are positioned at diametrically opposite points onsaid cam.

18. A method for continuously advancing. a web of sheet material througha machine having at least'one work station for intermittently operatingon said sheet material comprising the steps of:

engaging said sheet with a first engaging element and feeding said sheeta given distance through said machine with a forward stroke of a firstengaging element;

then engaging said sheet with a second engaging element which is movingat the same velocity as said first engaging element near the end of itsadvancing stroke, and thereafter releasing said sheet by said firstengaging element;

then returning said first engaging'element to the beginning of itsstroke while advancing said sheet with said second engaging element asecond given distance along said path;

then re-engaging said sheet with a first engaging element which ismoving at the same velocity as said second engaging element near the endof its advancing stroke, and thereafter releasing said sheet by saidsecond engaging element;

and moving said work station at the same velocity and direction as saidsheet during the intervals that said work station is operating on saidsheet.

19. A method according to claim 18 for continuously advancing a web ofsheet material through a machine having at least one work station forintermittently operating on said sheet material comprising the steps of:

successively performing the steps set forth in claim 18 a plurality oftimes. 20. A machine for working upon a continuous web of sheet materialcomprising:

means for directing said web in a predetermined path; a work stationpositioned along said path; means for continuously advancing said web ina forward direction along said path past said work station, saidadvancing means including first and second feed elements, each of saidfeed elements being mounted for reciprocating movement along said pathand each being adapted to intermittently engage and advance said webduring the forward motion of the element; said work station beingfixedly linked to one of said feed elements for reciprocating movementtherewith, and drive means for alternately reciprocating said feedelements, said drive means including a mechanical linkage connectedbetween said feed elements. 21. Apparatus comprising a supply ofmaterial in web form, a reciprocable work station for performing atleast one operation on said web, at least one reciprocable gripper forgrasping said web and advancing it past said work station, a single cam,and means connecting said single cam to both said work station and saidgripper to reciprocate said work station and gripper.

1. A machine for forming, filling, and sealing packages from a web ofmaterial being continuously transported past a series of work stations,said machine comprising: means for continuously advancing said web alonga path past said work stations including: a. a pair of clamp assemblieseach adapted to engage said web, b. means for mounting said clampassemblies for reciprocating movement in forward and reverse strokesalong said path, c. a rotatable cam, d. a pair of cam followers, e.means for linking each of said cam followers to a different one of saidclamp assemblies, and f. said cam and cam followers being adapted toreciprocate said clamp assemblies in an out-of-phase relationship witheach other; at least one of said work stations mounted for reciprocatingmovement with one of said clamp assemblies; said movable work stationincluding flat bed working elements movable with respect to said workstation in a path approximately perpendicular to that of said web andthe movement of said work station; means for actuating said workingelements to work upon said web while the clamp assembly with which thework station is mounted is engaging and advancing said web; and clampactuating means for alternately closing said clamp assemblies during aportion of their forward strokes, said clamp assemblies beingsimultaneously closed only when moving at the same velocity during theforward stroke; whereby said web is continuously moved in a forwarddirection by the alternative action of said clamp assemblies.
 2. Amachine according to claim 1 wherein said working elements include: areciprocating die assembly operable to deform said web when actuated. 2.deforming a heated portion of said web to form a plurality ofblister-like compartments therein,
 3. A packaging machine havingforming, filling, and sealing means for working upon a continuous web ofsheet material, said machine comprising: means for directing said web ina predetermined path; a flat bed work station positioned along saidpath; means for continuously advancing said web in a forward directionalong said path past said work station, said advancing means includingfirst and second feed elements, each of said feed elements being mountedfor reciprocating movement along said path and each being adapted tointermittently engage and advance said web during the forward motion ofthe element; and drive means for alternately reciprocating said feedelements, said drive means including a mechanical linkage connectedbetween said feed elements.
 3. loading articles into said formedcompartments,
 4. laminating a film to a portion of said web to seal saidloaded compartments, and
 4. A machine according to claim 3 wherein: saidwork station is fixedly linked to one of said feed elements forreciprocating movement therewith.
 5. A machine according to claim 4wherein said work station includes: a working member for working uponsaid web and mounted for reciprocating movement on said movable workstation in a path approximately perpendicular to the path of said weband saId work station.
 5. trimming a sealed portion of said web to forma package; and means for continuously advancing said web along a pathpast said work station comprising: a. a pair of clamp assemblies adaptedto engage said web, b. means for mounting said clamp assemblies forreciprocating movement in forward and reverse strokes along said path,c. a rotatable cam, d. a pair of cam followers, e. means for linkingeach of said cam followers to a different one of said clamp assemblies,f. said cam and cam followers being adapted to reciprocate said clampassemblies in out-of-phase relationship with each other; and g. clampactuating means for alternately closing said clamp assemblies during aportion of their forward strokes, said clamp assemblies beingsimultaneously actuated only when moving at the same velocity during theforward stroke; whereby said web is continuously moved in a forwarddirection by the alternative action of said clamp assemblies.
 6. Amachine according to claim 5 further comprising: means for actuatingsaid working element to work upon said web while the sheet feed memberwith which the work station is mounted is engaging and advancing saidweb.
 7. A machine according to claim 3 further comprising: means foractuating said feed elements to engage said web during the forwardmovement of the element but to disengage said web during the returnmovement of the feed element; said feed elements being moved at the samevelocity in the forward direction during periods near the beginnings andthe ends of their forward movements, said elements momentarilysimultaneously engaging said web during said periods; whereby said webis continuously being engaged and advanced by at least one of saidelements.
 8. A machine according to claim 7 wherein: said elements aredriven at an approximately constant velocity when engaging said web. 9.A blister packaging machine comprising: a supply of thermoplastic sheetmaterial in the form of a web; a plurality of work stations forsuccessively performing, upon said web, the operations of
 10. A machineaccording to claim 9 wherein: at least one of said work stations mountedfor reciprocating movement with said clamp assemblies; said movable workstation including working elements movable with respect to said workstation in a path approximately perpendicular to that of said web andthe movement of said work station; and means for actuating said workingelements to work upon said web while the clamp assembly with which thework station is mounted is engaging and advancing said web.
 11. Amachine according to claim 10 wherein said movable work stationincludes: a die forming assembly having an element movable against saidweb to deform said web while said station is moving at the same velocityas said web.
 12. A machine according to claim 10 wherein said movablework station includes: a heater assembly having an element movableagainst said web to heat said web while said station is moving at thesame velocity as said web.
 13. A machine according to claim 10 whereinsaid movable work station includes: a press assembly having an elementmovable against said web to laminate to said web an interposing filmmaterial while said station is moving at the same velocity as said web.14. A machine according to claim 10 wherein said movable work stationincludes: a die cutting assembly having an element movable against saidweb to cut said web while said station is moving at the same velocity assaid web.
 15. In a machine for working upon a web of sheet material at awOrk station, means for continuously advancing said web along a pathpast said work station comprising: a pair of clamp assemblies adapted toengage said web; means for mounting said clamp assemblies forreciprocating movement in forward and reverse strokes along said path, arotatable cam; a pair of cam followers; means for linking each of saidcam followers to a different one of said clamp assemblies; said cam andcam followers being adapted to reciprocate said clamp assemblies inout-of-phase relationship with each other; and clamp actuating means foralternately closing said clamp assemblies during a portion of theirforward strokes, said clamp assemblies being simultaneously actuatedonly when moving at the same velocity during the forward stroke; wherebysaid web is continuously moved in a forward direction by the alternativeaction of said clamp assemblies.
 16. Advancing means according to claim15 wherein: each of said clamp assemblies includes a pair of elongatedclamps extending along said path and on opposite edges of said web, saidclamp assemblies being positioned to engage said edges when closed. 17.Advancing means according to claim 15 wherein: said cam includes a majorportion of uniformly increasing radius; and said cam followers arepositioned at diametrically opposite points on said cam.
 18. A methodfor continuously advancing a web of sheet material through a machinehaving at least one work station for intermittently operating on saidsheet material comprising the steps of: engaging said sheet with a firstengaging element and feeding said sheet a given distance through saidmachine with a forward stroke of a first engaging element; then engagingsaid sheet with a second engaging element which is moving at the samevelocity as said first engaging element near the end of its advancingstroke, and thereafter releasing said sheet by said first engagingelement; then returning said first engaging element to the beginning ofits stroke while advancing said sheet with said second engaging elementa second given distance along said path; then re-engaging said sheetwith a first engaging element which is moving at the same velocity assaid second engaging element near the end of its advancing stroke, andthereafter releasing said sheet by said second engaging element; andmoving said work station at the same velocity and direction as saidsheet during the intervals that said work station is operating on saidsheet.
 19. A method according to claim 18 for continuously advancing aweb of sheet material through a machine having at least one work stationfor intermittently operating on said sheet material comprising the stepsof: successively performing the steps set forth in claim 18 a pluralityof times.
 20. A machine for working upon a continuous web of sheetmaterial comprising: means for directing said web in a predeterminedpath; a work station positioned along said path; means for continuouslyadvancing said web in a forward direction along said path past said workstation, said advancing means including first and second feed elements,each of said feed elements being mounted for reciprocating movementalong said path and each being adapted to intermittently engage andadvance said web during the forward motion of the element; said workstation being fixedly linked to one of said feed elements forreciprocating movement therewith, and drive means for alternatelyreciprocating said feed elements, said drive means including amechanical linkage connected between said feed elements.
 21. Apparatuscomprising a supply of material in web form, a reciprocable work stationfor performing at least one operation on said web, at least onereciprocable gripper for grasping said web and advancing it past saidwork station, a single cam, and means connecting said single cam to bothsaid work station and said gRipper to reciprocate said work station andgripper.